Analysis Of Yield,Quality And Benefit For Different Cultivation Methods Of Wheat Following Rice

The wheat yield per unit area has been increased continuously in China,ensuring cereal security.However,there still exist many issues,including excessive fertilizer application,low nitrogen utilization efficiency,unstable grain quality,and serious environmental pollution caused by residual fertilizers.Besides,the decreasing wheat planting benefit has directly affected farmers' planting intention.Therefore,the practice problems urgently needed to be solved is how to improve grain quality and fertilizer utilization efficiency simultaneously,while ensuring cereal supply for the nation,to form an environment-friendly and agricultural sustainable development situation.With medium-gluten wheat cultivars Yangmai 25,Huaimai 3,and weak-gluten cultivar Yangmai 22 as materials,the experiments were conducted in the middle and lower reaches of the Yangtze River(Suining and Yangzhou),a main wheat-producing area used the rice-wheat rotation,to study a conventional cultivar method and different optimized methods.These methods were established through planting density,fertilizer application rate,application stage,and application ratio depending on the current field production.The present study aims to analyze the performance of grain yield,nitrogen utilization efficiency,grain quality,and economic benefit under the above-mentioned cultivation methods,propose the relatively optimized methods suited for the planting of medium-gluten or weak-gluten wheat,and illustrate the formation mechanisms of the population established by these methods by analyzing the yield composition characteristics,agronomic characteristics,and physiological characteristics.The expected results can provide theoretical and practical references for good-quality,high-yield,and high-efficiency cultivation of wheat following rice in the middle and lower reaches of the Yangtze River.The main results are as follows:1.In the suitable growth condition year(2017?2018),the optimized cultivation method increased grain yield,nitrogen agronomy efficiency,nitrogen apparent utilization efficiency,nitrogen partial factor productivity,and net benefit of medium-gluten wheat varieties Yangmai 25 and Huaimai 33 at most by?30%,?55%,?15%,?53%,and?93%,respectively.This method improved nitrogen efficiency based on stabilizing high grain yield,ensured high net benefit,reduced the soil residual nitrogen content,and the negative impact on the soil environment,but the grain quality still has the potential to be improved.In the poor climate condition year(2018?2019.too much rainfall at the seedling stage),the optimized cultivation method relative to the conventional method increased grain yield,nitrogen agronomy efficiency,nitrogen apparent utilization efficiency,and nitrogen partial factor productivity of the two varieties mentioned above at most by?3%,?28%,?40%,and?8%,respectively.The improved method produced high-quality grains of medium-gluten wheat,but the net benefit was lower under this method than under the conventional method with a higher content of residual soil alkali hydrolyzed nitrogen,indicating a needed improvement2.In the suitable growth condition year,the optimized cultivation method increased grain yield,nitrogen agronomy efficiency,nitrogen apparent utilization efficiency,and nitrogen partial factor productivity of weak-gluten wheat varieties Yangmai 22 at most by?2%,?3%,?7%,and?19%,respectively,compared with the conventional method.The improved method improved grain yield and nitrogen efficiency and reduced the residual soil nitrogen content,while its grain quality achieved the national standard of high-quality weak-gluten wheat,but the net benefit was not increased significantly by this method.In the poor climate condition year.Yangmai 22 had obvious advantages in grain quality,net benefit,and residual soil alkali hydrolyzed nitrogen content under the conventional method,except that there was a lower nitrogen efficiency compared with the optimized methods.The other improved cultivation methods showed a higher nitrogen efficiency,including nitrogen agronomy efficiency,nitrogen apparent utilization efficiency,and nitrogen partial factor productivity,which was increased at most by?23%,?17%,and?7%,respectively.Besides,their grain quality met the standard of high-quality weak-gluten wheatIn conclusion,the cultivation methods constructed by integrated measures can achieve the goal of high yield,good quality,and high efficiency,but the synergy level and improvement potential of these parameters depend on climate,ecology,growth condition,and varieties.The synergy level of these parameters with the adopted methods of medium-and weak-gluten wheat is better in the suitable growth condition year than that in the poor climate year,while the medium-gluten cultivars are better than the weak-gluten cultivars Besides,the improvement potential of high yield and high efficiency is higher for medium-gluten cultivars than weak-gluten cultivars;weak-gluten cultivars are easy to achieve the synergy of high yield,good quality,and high efficiency,but with a lower improved potential3.The results on yield composition showed that,in the suitable climate year,the number of spikes and 1000-grains weight were the critical factors determining the grain yield of medium-gluten and weak-gluten wheat.Coordinated improvement of the number of grains per spike and 1000-grains weight based on achieving a higher number of spikes was conductive to achieve the goal of good quality,high yield,and high efficiency.However,there were insufficient stems and tillers of the wheat population in the poor climate condition year.Therefore,it is necessary to strengthen the basis of the spike number and improve the yield components in coordination to build a high-quality,high-yield,and efficient wheat population effectively4.The results on population quality showed that,in the suitable climate year,the medium-gluten and weak-gluten wheat population needed to maintain a high tiller number at the early growth stage and improve the tiller fertility with a significantly higher tiller number at the maturity stage,which provided sufficient spikes for high quality and yield of grain.The medium-gluten and weak-gluten wheat populations with high-quality,high-yield,and high-efficiency maintained a high dry matter accumulation and a strong photosynthetic production capacity after anthesis,and increased photosynthetic matter accumulate after jointing.In the poor climate condition year,the population with high quality,high yield,and high efficiency of medium-gluten wheat maintained a relatively stable dynamic change of the stem and tiller number and higher fertility.The tiller number of weak-gluten wheat populations maintained at a high level during the whole growth period to ensure a sufficient population number.The high-quality,high-yield,and high-efficient populations of medium-gluten wheat accumulated enough photosynthetic substances at the early growth stage,while accumulated enough photosynthetic substances at the late growth stage,especially after flowering,to improve the contribution ratio of photo synthetic products to the grain.Due to low fertilizer efficiency at the early stage,the population with high quality,high yield,and high efficiency of weak gluten wheat was not well developed,so the dry matter accumulation was increased as much as possible to maintain the stable development of the populations.5.The wheat population with high quality,high yield,and high efficiency of medium-gluten and weak-gluten wheat showed a higher green leaf area,flag leaf net photosynthetic rate,and SPAD value.The activities of SOD,POD.and CAT in the flag leaves under the optimized cultivation methods were higher than those in the other improved modes with lower MDA content.Besides,the activities of NR and GS in flag leaves under the optimized cultivation methods were higher.Under different cultivation methods,the changes in nitrogen accumulation,nitrogen transportation,and nitrogen harvest index were consistent with the changes in grain yield.Therefore,the high level of nitrogen metabolism in leaves and the high ability of nitrogen absorption and transport in plants are the essential physiological basis for high quality,high yield,and high efficiency.Besides,these physiological characteristics facilitated to improve the absorption of soil nitrogen and reduce the soil nitrogen residue.6.The results of medium-gluten wheat showed that,in the suitable climate year,the specific measures of the optimized cultivation method include:(1)the basic seedling of 180×104·hm-2,the total nitrogen fertilizer application of 240kg·hm-2,the ratio of fertilizer application at the stages of pre-sowing,tillering,jointing,and booting with 5:1:2:2,the total application amount of potassium and phosphate fertilizer(P2O5,K2O)of 120kg·hm-2 with the ratio of 5:5 at pre-sowing and jointing stages,or(2)the basic seedling of 225×104·hm-2.the total nitrogen fertilizer application of 210kg·hm-2 with the ratio of 3:1:3:3,and the total application amount of potassium and phosphate fertilizer of 105kg·m-2 with the ratio of 5:5.The measurements,including suitable seeding density,suitably increased nitrogen rate with an improved application at the late stage and a high amount of phosphate and potassium fertilizers,facilitate achieving the following aims:ensuring high grain yield,improving nitrogen efficiency,maintaining a high net economic benefit,and reducing the residual soil nitrogen content.In the poor climate condition year,the specific measures of the optimized cultivation method include the basic seedling of 180×104·hm-2,total nitrogen fertilizer application of 240?270kg·hm-2 with the ratio of 3:1:3:3,and the total application amount of potassium and phosphate fertilizers of 120?135kg·hm-2 with the ratio of 5:5.Higher seeding amount can increase the population number.Besides,an appropriate increase in the nitrogen fertilizer application at the late growth period can improve the nitrogen fertilizer efficiency based on increased grain yield,while producing good-quality grains of middle-gluten wheat.7.The results of weak-gluten wheat showed that,in the suitable climate year,the specific measures of the optimized cultivation method include(1)the basic seedling of 180×104·hm-2,the total nitrogen fertilizer application of 240kg·hm-2 with the application ratio of 5:1:2:2,total application amount of potassium and phosphate fertilizers of 120 kg·hm-2 with the ratio of 5:5,or(2)the basic seedling of 225×104·hm-2,the total nitrogen fertilizer application of 210kg·hm-2 with the ratio of 7:1:2:0,and the total application amount of potassium and phosphate fertilizer of 105kg·hm-2 with the ratio of 5:5.Appropriately reduced nitrogen,phosphorus,and potassium fertiliers during the growth period of wheat but increased nitrogen at the early stages can achieve the purpose of ensuring a stable grain yield,reducing grain protein content,and improving the grain quality of weak-gluten wheat.In the poor climate condition year,the specific measures of the optimized cultivation method include the basic seedling of 270×104·hm-2,the total nitrogen fertilizer application of 270kg·hm-2 with the ratio of 6:1:3:0,the total application amount of potassium and phosphate fertilizer of 94.5kg·hm-2 with the ratio of 5:5.The increased seeding rate at the early stage,nitrogen fertilizer rate,and nitrogen application at the early stage can result in increased population number and grain yield,optimized grain quality of weak-gluten wheat,improved economic benefits,and reduced residual soil nitrogen content.